Table 1 Grading system of the modified Matsumoto’s classification

Decrease in signal intensity of intervertebral disc

0: As bright as or slightly less bright than healthy disc

1: Markedly darker than healthy disc

2: No signal

Posterior disc protrusion

0: No protrusion

1: Disc material protruding beyond the posterior margin of the vertebral body without cord compression

(less than one-third of dural sac)

2: Beyond vertebral body with cord compression (more than one-third of dural sac)

Disc space narrowing

0: 100–75% of height of upper healthy disc

1: 75–50% of height of upper healthy disc

2: Less than 50% of height of upper healthy disc